cerebro como los lóbulos frontales generan las funciones ejecutivas en una
progresión lineal. También hacemos una breve exploración de la naturaleza
de la consciencia humana y de las dificultades para medir las funciones
ejecutivas. Utilizando los cambios producidos en el cerebro a causa del
alcohol, en ejemplos cros-culturales, intentamos deficir una
neuroepistemología para comprender la relación dinámica entre el
funcionamiento ejecutivo y la consciencia. Palabras clave: evolución
cerebral, funcionamiento ejecutivo.
Hunting is of no particular value when you can herd. This comment,
from one of the few biohistorians in existence, summarises what one finds in
the literature on the development of speech, forearm pronation, erect stature,
and so on in the archihistory of the hominids (McElvaine, 2000). Five
million years ago, we split from the chimpanzees. Four million years ago,
Homo Erectus arose from all fours, and two million years ago, bodies and
brains and tools interacted, with Homo Habilus having much more success
now that the forelegs were free. The rotation of the radius over the ulna in
the forearm allows for pronation, and the hands and digits are free, enabling
such future tasks as manipulating a computer keyboard.
Being on all fours, with claws and jaws has its advantages. With
binocular forward vision, a predator is equipped for the visually guided
chase. Visual working memory is essential, so are the abilities to
communicate on a simple level, and with this, the ability to produce tools is
also of evolutionary significance. If you can advance your equipment during
your lifespan, you need to chat about it to others, and pass the skill along the
The erect, toolmaking-talking stance too has its advantages: evolution
allows little by chance, all is finally linked with a purpose, with evolutionary
advantage the driving force. The modern- looking human emerges a scant
130,000 years ago, and 50,000 years ago, there is a modern agrarian society
(Conway Morris, 2001).
The erect toolmaking-talking stance has its disadvantages as well, more
than just varicose veins and premature birth. With the loss of claws and
jaws, speech and keyboard typing are released as future possibilities;
however, a biped is easily outrun by a predatory quadruped, and when
caught, a clawless, fangless creature is at a disadvantage, certainly when
alone. These disadvantages, which allow for effective use of the pronated
forearm and the articulated buccal cavity, need to be balanced by choosing
other paths to follow socially.
How evolution made choices is not always clear. There is emerging
evidence from evolutionary biology that the brain is not a tabula rasa to be
EVOLUTION AND EXECUTIVE FUNCTIONS
shaped by society, but most likely an organ that has adapted over time in
order to deal with its changing environment. This is done by solving the key
problems of social competition and cooperation (Francis Fukuyama, 2001;
The first of the choices evolution makes in order to deal with these key
problems indicates at some level the use of an experimental approach with a
control. In this instance, the right hemisphere represented the more static
‘control group’. In evolutionary terms, this early brain was a success, with
the right side structures and functions mirrored in a laterally redundant brain:
injury to the right or left side would leave the contralateral structure and
function intact to fill in the gaps in performance. This was a good
evolutionary tactic, and at that time, the forces of evolution could allow for
specialisation of the left hemisphere. This created a dominant, left
hemisphere with the capacity for more complex speech and now handedness,
mostly dexterous, but more importantly, this enabled an ability to take a
meta-perspective of the functioning of the right hemisphere (Barkley, 1998;
Gazzaniga, 2000), a method of enabling humans to be humans with
consciousness of that fact. Such a meta-perspective probably involved the
use of internal language, or thought, and thus the emergence of a more
mature set of internal controls on many levels, which would now
At first, emotion was unconscious and sufficient to allow for choices to
be made (Damasio, 2000). Intentional control was left to the right
hemisphere (Heilman & Watson, 1991). The growing awareness of what
was emotional valence in decision-making came to enhance the organism's
choices and functions:
“I suspect that in earlier stages of evolution….emotions –were
entirely unknown to the organisms producing them. The states were
regulatory and that was enough; they produced some advantageous
actions, internally or externally, or they assisted indirectly the
productions of such actions by making them more propitious. But
the organisms carrying out those complicated operations knew
nothing of the existence of those operations and actions since they
did not even know, in the proper sense of the word, of their own
existence as individuals” (Damasio, 2000; p 30).
Evolution was faced with another choice: in this case the evolution of
society meant the evolution of social competition (Sugarman, 2000). A
creature that evolves to make fantastic tools at the cost of increasing physical
vulnerability is faced with the need to aggregate (Barkley 1998).
The other possibility is that a creature that can make tools no longer needs
physical prowess or for that matter, isolation as a way of life is over with.
The likelihood however is that social aggregation grew out of necessity, and
together with the development of advanced speech from two million to
50,000 years ago, humans developed the wherewithal and the need to build
communal shelters, to bury their dead in graves, and chat about it all
(Conway Morris 2000). It was also largely the end of at least some of the
more terrible forces of natural selection, as the environment lost the sheer
unmitigated weight of its predatory component, but gave humans the power
of meta-cognitive internal process. Hominids would now have to “mount
somatic states to complex stimuli charged with social significance”
(Damasio, Tranel & Damasio 1991; p 222). Ideas could be shared or
bartered, and whilst environment still played the role it always had,
environmental factors now made people different from, rather than similar
to, their relatives, whilst nearly all behaviours showed otherwise moderate to
high heritability (McGuffin, Riley & Plomin, 2001), and self-regulation a
very high heritability (Barkley 1998).
Hence a new social pressure emerged: with the verbal, communal
processing of creative information; public behaviour was now open to the
scrutiny of nearby kinfolk, and thus socially competitive behaviour would
become a new source of natural selection: ideational Darwinism if you will
(Barkley, 1998; Sugarman, 2000).
In order to effectively aggregate previously disinhibited hominids, social
rules had to evolve and hence the evolution of rituals. In order to effectively
compete, a system had to emerge whereby previously public behaviour
became more private, more internal. This obeying of rules could now be
transmitted by verbal agreement, and together with the aforementioned
burial of public behaviour, internal rule-governed behaviour was to become
a two-headed coin. Rule-governed behaviour implies inner control: both
sides of this coin require inner speech. Homo Sapiens in this way thwarted
some of the very evolutionary forces that created this upright, left-
hemisphere-dominant, thinking, speaking, tool-using hominid. In order to
pass on the skills of toolmaking whilst staying competitive, the hominid
needed to be able to both speak, and hide such speech when necessary, pass
on rules, and have an internal system to control and utilise such rules
internally, all under volitional control: it was the birth of self-regulation and
inhibition via internal meta-analysis and meta-cognition.
The sine qua non of this self-reflexive, pensive, internal, self-regulating
languaging was that one aspect of internal language could remain ‘meta’, or
in executive judgement over another, allowing a behaviour to be judged
EVOLUTION AND EXECUTIVE FUNCTIONS
within a class of behaviors, with the risk of confusing the two. Meta-
cognition allows thinking about thinking, and this is describing a second-
order cybernetic process. Aspects of the content of such processes requires
illumination and definition, if measuring such processes is to take place with
better than face validity, or without the spectre of reductionism.
Verbal Working Memory, self-regulation and inhibition
From a reading of Baddeley’s 1995 work it becomes clear that verbal
working memory lies at the base of all executive functioning. This is clearly
Barkley’s public speech made private. A lone solitary, semi-upright
creature with jaws, claws, and primitive weapons was not enough of a
guarantee for advantageous evolution. An upright biped with various levels
of abstraction in outward and inward systems of language was necessary for
further evolutionary advantage. Medial limbic circuits certainly had
developed to mediate information related to internal states, important
aspects of memory and learning, connections with sexual-visceral and
endocrine functions. Lateral limbic circuitry however now evolved to
mediate information related to the body surface, external world and social-
personal interactions, empathy, social cognition, mood and civil behaviour
(Trimble, Mendez & Cummings 1997). Internal and external worlds could
now communicate across the temporal lobe.
But in the same way as external language became important, so now was
private behaviour. Fire-making skills are one thing; preserving the genetic
line with full advantage requires a selective approach to information
processing and display. One gives to one’s offspring the advantage
selectively if one can, not to the world at large, at least, not willingly.
Choice is the privilege of those who can consider the options quietly, in
private, in pictures and in words, before the event that will weigh heavily,
necessitating sentience of mind.
A child is born with visual working memory, and by adulthood has a
fully developed working memory as well. Verbal and visual working
memory later come together to allow for the acquisition of culture,
socialisation and creativity (Barkley, 1998). Initially the child may render
its experiences out loud, but from 5-10 years old, the speech quietens and
becomes more internal, leaving only micro-electronic evidence of
evolutionary antecedence (Russell Barkely, references supplied by personal
communication). Once the human internalises the communities rules, the
actualisation of these as internal systems of governance depends on cultural
integrity within and externally, in a recursive and evolving way, much as
modern courts interpret and modify law. Intelligence plays a role.
In David Wechsler’s 1944 definition, intelligence is the global or
aggregate ability to act with purpose, to think rationally, and to deal
effectively with the environment (Walsh, 1992). To act with purpose
suggests an appreciation for goal-directed activity and also an appreciation
of the connected continuity of events across time. To think rationally
applies purpose to thinking, namely an ability to run an approximation of
connected past, present and future events through a simulator comprising of
internal speech and vision. To deal effectively with the environment implies
both volition as well as a widespread processing system that will measure
external outcomes by integrating multi- and heteromodal incoming
information across time against both purpose and rationale, and to compare
the results in an ongoing way across temporal history. As Damasio, Tranel
& Damasio write in 1991:
“Because there is no single neuroanatomic region that holds the
integrated “image” of a polysensory based set of events, meaning is
critically dependent on timing. And because implied meanings
require a far larger set of components for their definition than
manifest meanings do, the problem of synchronisation and
subsequent attention looms larger. In short, from this perspective,
the response selections required for appropriate decision making in
social cognition and equivalent realms, necessitates the holding on
line, for long periods of time (in the order of several thousand
milliseconds), highly heterogeneous sets of cognitive components
that must be attended effectively, if a choice is to be made” (pp 219-
Working memory is thus the imperative force that guides internal human
volition, goal setting, and effective action, as Lezak framed executive
functions (Lezak, 1982; 1995). It is also clearly heteromodal, requires large
areas of heteromodal cortex, and damage limits conscious awareness across
time (Prigatano 1996). In Mesulam’s formulation, these areas provided a
fairly faithful representation of what the outer world is all about, or
providing what we call our phenomenological or subjective experiences
(Prigatano 1996). The idea of emotional valence, or what it means to attach
an emotion to such experience will be discussed further on. In the meantime
though, it is reasonable to see conscious awareness, or an appreciation of the
verbal/visual simulator, as an offshoot of this application of intelligent
executive meta-functioning of working memory. An interaction between the
outside and inside milieus across time creates an awareness of both, and
EVOLUTION AND EXECUTIVE FUNCTIONS
given varying levels of internal consideration, certain logical approaches are
prescribed, and others proscribed, consciously and with presience of mind.
Defining the parameters of executive functioning as a dynamic
Defining aspects of executive functioning as Lezak has done is helpful,
but may be reductionistic. By this I mean that a circular and homeostatic
mechanism may not be reduced to its components parts without running into
logical paradoxes, as Lezak, to her credit, notes (Lezak, 1995) in the
fractionation of executive functions. Language is linear, and without careful
definition, the pragmatic aspect of language reifies concepts that then induce
individuals to create tools to measure their linear strength, and then apply
this as if it were a measure of the circular events themselves. In linear terms,
action ‘A’ causes result ‘B’ (such as hitting someone). In circular
epistemologies, action ‘A’ influences not only result ‘B’ but in turn
influences ‘A’ in a recursive interaction (by applying feedback, such as
complaining to the law).
There is no surprise then that metaphors created by Freud, such as Ego
and Super Ego, were then subject to measurement instruments as if the
metaphor represented a real continuous linear ‘thing’, and not a process, as
has happened with executive functions. Time and paradox are strongly
interconnected (Watzlawick, Beavin & Jackson, 1967), and any definition of
a process should consider the interaction of time and content.
Barkley (1998) set out to define how working memory influences
inhibition and self-regulation, and how these then interact with the so-called
executive functions. His is one of the few formulations that use an
appreciation of temporally distant events as part of the definition of the
dynamic activities of self-regulation. Gualtieri (1995) earlier summarised
the same kind of approach in passing, but without formal definition, or
reference to time and class of events:
“Self regulated behaviour in humans also requires the development of
guidance systems and programs that are appropriate to a chosen goal,
flexible in the face of obstacles, protected from extraneous or internal
distractors, and liberated from the proactive interference of previously
learning programmes (p157)”,
and is referring to the principle of autonomy since this must all occur in the
absence of extenal direction or structure (p153). He does however note that
“conceptual thinking comprises the ability to draw abstractions from
perceptual experience and to manipulate abstract ideas in an organised
and effective way” (p 152)
without reference to the different levels of abstraction evident in such a
formulation, or the essential nature of the passage of time.
As far back as 1920, Head noted that brain activity at any moment is not
an isolated event, but rather is related to the brain’s activity of a moment
before; Greenfield in 1995 identified aminergic neuromodulation as
evidence of the contingency of previous neural and neurochemical events on
a neuron’s functioning (see references cited and argument in Mazabow,
1999). In short, icons of information need to be echoic for perception to take
The first concept, response inhibition, is defined in Barkley’s terms as
the innate capacity to inhibit a ‘prepotent’ response, namely, that response
that is reinforced by the immediate environment in which one finds oneself
at any given moment. This implies the ability to ponder about, or delay a
decision about a response, as well as the capacity to interrupt any response
when the feedback information is that this response is not having the desired
effect. This also implies the capacity otherwise to avoid competing
responses which act as distractors. Efficient working memory thus underlies
this pondering-monitoring process, and is clearly self-recursive in that it
involves both outer and inner worlds in circular interaction across linear
time, with the goal of homeostasis.
The second linked concept, self-regulation, includes any self-directed
intervention that changes a present/future behaviour so as to alter a
temporally distant, likely outcome. The elements of this are that this:
• Is self-directed (internally, silently mediated)
• Relies on internal utility of outcome (a value system that observes
• Is future-orientated in that the future is valued over the present
• Requires a special form of sequential working memory (icons that are
• Bridges uncertain outcomes by allowing for contingencies (abstract
• Binds events across time (related to the special sense of temporal events
in logical sequence)
What is also clear from studies cited elsewhere by Barkley, is that the
further forward in the future a favourable outcome may be, the more
prefrontal cortex is needed. Executive interactions are thus strongly
intertwined with future outcomes based on this connected quality of the
events upon which the process focus directs, and is linked to the social
EVOLUTION AND EXECUTIVE FUNCTIONS
environment. (Burgess et al. 1998, see reference below) note that this
particular form of sequential memory, the correct ordering of events in
memory, is best described as executive memory, pathology here related to
Finally, the last and most troublesome concept is that of dynamic
executive functioning. Following on the above, executive functioning is best
described as those forms of self-directed activity that delay prepotent,
unfavourable responses, and replace these with behaviour that binds events
across time in order to favourably alter future outcomes.
The high functioning human may thus wrest control of life outcomes
from the environment by judicious usage and overview of the events in
working memory. This is simulation, again, an internal process of
premeditation, and this is the process that influences natural selection, or the
pruning of the environmentally disadvantaged.
A failure of such a (circular/homeostatic) mechanism must result in poor
social functioning, and a despairing resort to other (more linear, perhaps
pathological first-order) mechanisms, such as social aggression, social
manipulation, social withdrawal, and so on (Sugarman, 2000). This would
then result in social withdrawal being a common, non-specific, almost
invariate sequel to serious mental dysfunction, and in a review of the
available literature, this indeed appears to be the case (Sugarman, 2000). In
other words, when homeostasis, a second order phenomenon breaks down,
simpler, more first order solutions are attempted, linear shots across the bow
as it were.
Executive function as a process can thus be seen to have a content to it,
as well as the meta-analytic ability of self-reflection. However, in itself,
executive functioning is not merely content, but a process, and to compare
and confuse the two is to make a class of actions a member of the class itself,
an epistemological error that will bedevil attempts to measure it reliably
(Dell 1982; Watzlawick, Weakland & Fisch, 1974).
Over-analysing this content may lead to fractioning of the dysexecutive
syndrome, but there may be limits to this, such as the differential loading of
some tests on the factors of inhibition, intentionality and executive memory
(Burgess, Alderman, Evans, Emslie & Wilson 1998). These authors
conclude, with regard to the first aspect, that inhibition, is:
“inextricably bound up with concepts of “general intelligence,” and the
behavioural manifestations of deficits in these processeas are seen most
often as poor control of social behaviour” (p555),
an idea mirrored in the comments of Matarazzo (1990) some time before.
Burgess et al (1998) note that their findings are consistent with the view that
the executive functions, as a system, provide “control” (their emphasis)
functions for a wide range of more informationally encapsulated resources,
as put forward by the principle author the previous year. Hence different
tests measure different aspects of the dysexecutive syndrome, with poorer
representation of motivation and personality aspects; more attention is paid
to this below, with regard to motivation and emotion (see references to
The idea that this process of “control” is of a somewhat higher order of
abstraction than the other “informationally” encapsulated resources is again
put forward, suggesting the danger again of confounding logical confusion.
Epistemological confusion in systems theory
Whitehead and Russell (1910-1913) wrote of the theory of logical types.
In this theory, whatever involves all of a collective class must not be one of
the class itself. Any attempt to deal with one in terms of the other leads to
confusion and logical errors (quoted in Watzlawick, Weakland & Fisch
1974). By virtue of its position, meta-analytical thought, or meta-cognition
cannot be divided up into its component parts, and deliver information about
itself any more than one person is defined by dividing results on 10, 000
subjects by a factor of 10,000. Change to any system automatically involves
a higher level of abstraction, and hence from Barkley’s definitions, executive
functioning embodies changes in level and abstraction in thought processes
across time, and involves multiple and heteromodal aspects of brain
functioning. If there is a content which can be measured during the process
of thinking, e.g. the content of memory or of the hippocampal input-output,
then modifying or observing such a process from within implies another
level of abstraction, such as homeostatic process. Content and process are
two different entities, and to confuse the two leads to paradox. Yet
psychological assessment does just that in creating norm tables for the
assessment of executive functions (Lezak 1982; 1995). Testing and
assessment are again, two concepts at two different levels of abstraction.
Testing vs. Assessment: Matarazzo, Walsh and Damasio
Joseph D. Matarazzo, past president of the American Psychological
Association, said in his plenary address at his inauguration in 1990 that
psychological testing is not equivalent to psychological assessment
(Matarazzo, 1990). Reading further, it is clear that the content of testing is
not equivalent to the process of assessment, and to confuse the two is again
EVOLUTION AND EXECUTIVE FUNCTIONS
a confusion of one level with another level of abstraction, a meta-level. In
the same way, the content of IQ is normally distributed across its own
population, but the process of how that IQ is produced, namely the subtests,
themselves do not follow a normal distribution. Since the basis of all
normative testing is that the attribute being assessed is normally distributed,
norm tables for individual subtests are meaningless. Also then, it is
acceptable that intersubtest scatter is a function of normal human
performance. A normally distributed IQ cannot thus be broken down into
the sum of its parts with any indication of more than face validity.
Walsh (1992), in considering neuropsychological test equipment, notes
that all tests have only face validity, and that different persons fail the same
test for different reasons. Clinical Neuropsychology is, Walsh argues, a
matter of making inferences. In short, neuropsychological inferences
represent a meta-analysis of test outcomes, and as Matarazzo notes:
“Assessment…..is a highly complex operation that involves
extracting diagnostic meaning……Rather than being totally
objective, psychological assessment involves a subjective
component…..Objective psychological testing and clinically
sanctioned and licensed psychological assessment are vastly
different enterprises” (Matarazzo 1990; p 1000, italics in original).
One of the main concepts in modern clinical neuropsychology, from
Matarazzo’s work, and incorporating newer findings, is that single-aspect
functional output of the brain involves multiple neural substrata (Mazabow
1999), and therefore by inference, pathology of the human brain produces
individualised sequelae that do not represent a normal distribution. Despite
this, Lezak (1982) notes:
“Without assessment techniques that can be standardized and that
can produce data subject to statistical analysis, much of our
understanding of executive functions will remain at an anecdotal
In a sense, Lezak falls into the universalist trap that so often rears its head
in the field of transcultural neuropsychology, for which she is criticised
elsewhere when making species-wide comparisons (Nell, 2000). She deals
with the paradox of assuming that such complex operations are reducible to
content only in passing, despite her appreciation even in 1982 of the 2nd
order process that appears to be the basis for these functions:
“A look at some of the important differences between executive and
cognitive functions may help us appreciate why systematic
measurement of the executive functions has lagged so far
behind…..One distinction between cognitive and executive
functions lies in the kind of question each class of functions calls
for……The structure of the usual neuropsychological or
psychological examination makes it very difficult, if not impossible,
to observe some of the most important executive functions……” (pp
She was certainly even more aware of the nature of epistemological
confusion in 1995, and used the term ‘paradox’ in this regard. One of the
“important executive functions” will appear in Lezak, 1995 as ‘volition’, in
which the temporally distant will become part of the definition. Motivation
is one of the preconditions for volitional behaviour, and the awareness of
self. Again, executive functioning is seen to be dependent on conscious
awareness and motivation (Lezak, 1995; p 651), which Damasio equates
with emotion (Damasio 1994). What patients report in terms of self-
reference across studies and across cultures does not correlate with their
overall neuropsychological status, but what their relatives or caregivers
report, clearly does (Prigatano 1996).
Emotional valence, consciousness, and emotions in the ‘visceral brain’
Emotional valence is a term used in another context, that of a loss of
awareness of deficit after traumatic brain injury (Prigatano, 1996, with
reference to Weinstein’s work, and about Brodal’s stroke, written up in
1973). For the brain-injured individual with widespread heteromodal
cortical damage, the valence of the inner experience is lost, thus the outside
context is always to blame. For Brodal, he had to learn to re-experience his
internal sense of his body. This lead Prigatano (1996) to comment:
“It is a tremendous argument that consciousness is the highest of all
the integrative brain functions, and disturbance of brain function in
any way will alter consciousness in some capacity, even though our
ability to measure it may be quite far from what the
phenomenological experience is for the patient. If these problems
were all psychiatric or purely straight-forward neurological
problems, these patients would have not shown it” (p 17,
transcription by R Sugarman, 1996).
Awareness is clearly cleaved off from mood (Prigatano, 1996,
commenting on Starkstein’s 1992/1993 work) as much as IQ is cleaved off
from executive functioning (Barkley, 1998). Prigatano believes there are
interactive variables that change with time.
Meta-analysis is thus the ability to stand apart from the content, and in a
process-oriented way, examine the process itself. Bringing together the
EVOLUTION AND EXECUTIVE FUNCTIONS
object and itself, as Damasio (2000) defines it, comprises a unified mental
pattern from its basic to most complex levels, and thus defines human
conscious awareness. It is clear from his work that Damasio regards one of
the issues of defining the neuroepistemology of consciousness is that of
meta-analysis as a twofold problem, that of simulating reality, and secondly:
“Generating the appearance of an owner and observer for the movie
within the movie; and the physiological mechanisms…..have an
influence on the mechanisms behind the first (p11)”.
There is thus a basis here for why the interaction between tester and test-
taker influences the quality of executive functioning, or the creation of what
Walsh has termed ‘surrogate frontal lobes’. The extent to which so many
authors resort to the use of metaphors is also interesting, as in post-modern
systemic thought, metaphor also has credentials as second order process.
Damasio also has difficulty with the reductionism of those such as
Starkstein, and comments that separating these two interactional entities is
the same as breaking consciousness into parts, and in so doing, making the
investigation of consciousness manageable, as has been done in analysing
executive functions by fractioning. Consciousness and emotion are not
separable, so that biological consciousness has several levels of organisation
and depends on conventional memory and working memory (Damasio,
2000, p16). That Damasio shares the view that this is all a second order
cybernetic process is also likely, given his comment that consciousness
consists of constructing knowledge about two facts, namely, that the
organism is involved in relating to some object, and that the object in the
relation causes a change in the organism (p20). Mazabow has argued that
this reflects on a cybernetic system that is partially open and partially closed,
but still capable of self-creating and self-regulating (autopoietic in the von
Glasersfeld tradition: Mazabow, 1999). Mazabow was working with the
strongly afferent/efferent connections of the visual system, as much as
Blessing (1997) is interested in the afferent/efferent connections of the
True to the tradition of Maturana and Varela, Damasio notes that the
organism in the relationship play above relies on the brain-based simulator
provided by Barkley’s model, “holding within itself a model of the whole
thing” (p22), a thought akin to Blessings “visceral brain” (Blessing, 1997).
Damasio refers to this visceral brain as perhaps the single most important
clue to the substance of the unconsciousness. Damasio comments later:
“ If actions are at the root of survival and if their power is tied to the
availability of guiding images, it follows that a device capable of
maximising the effective manipulation of images in the service of
the interests of a particular organism would have given enormous
advantages to the organisms that possessed the device and would
probably have prevailed in evolution” (2000; p 24).
Blessing (1997) appears critical of Damasio’s earlier work (‘Descartes
Error’ in 1994), but Damasio (in Damasio, Tranel & Damasio, 1991) had
even earlier noted:
“Activation of the amygdala would in turn result in reenactment of a
somatic state whose signal, intensity, and somatic distribution would
be pertinent to the sensory set” (1991; p225).
Damasio et al.’s model appears, at face value at least, to meet Blessing’s
criteria of homeostasis, taking in a wider view of the limbic-emotional areas
than did earlier writers.
A concept vital to self-regulating mechanisms is that of dynamic
homeostasis, a second-order cybernetic entity that follows the universal laws
of thermodynamics and is involved in the evolutionary task of maintenance
of the organism in its environment.
Dynamic homeostasis: dynamic assessment of ‘the right stuff’?
A careful reading of the above demonstrates that the process of conscious
self-regulation is not unlike the unconscious processes of self-regulation, and
thus represents homeostasis, hard to evaluate if the central nervous system is
closed off from other areas. As Blessing writes:
“It is likely that darwinian natural selection has resulted in the
development of patterned commands that integrate visceral and
behavioural components of bodily homeostasis, without the
necessity for immediate feedback…….Mammals have so evolved
that the programs that encode both the physiological and the
behavioural patterning necessary for survival are contained within
the brain, not in peripheral ganglia…..Our studies of bodily
homeostasis can then take place in a wider context. Thus in a study
of fluid and electrolyte balance, observations of behavioural
strategies used to find water and salt in deficient environments will
take their place along with relevant hormonal and neural control of
absorption and excretory mechanisms“ (Blessing, 1997, p 236).
Blessing clearly has a strongly homeostatic view of nervous regulation of
human behaviour. He comments (as noted above) that a critical reading of
Damasio (1994) with regard to isolating elements of limbic cortex or other
area of the brain has little to offer. Blessing reminds us of Brodal’s view
that one must be careful not to substitute names for explanations (Blessing,
EVOLUTION AND EXECUTIVE FUNCTIONS
1997). Conscious awareness in the Damasio (2000) context however,
emerges as a ‘feeling of what happens’ and allows for an appreciation of
object-agent relationships that are an essential part of wresting control from
the environment as Barkley defines executive control (vide infra). One has
to be aware at some level of the object (environment) and the agent (one’s
self) in order to simulate the outcome ahead of time. In other words, the
capacities for formulating future outcomes that are perceived as favourable
to the organism (goals), determining by simulation what steps must be taken
(planning), and the effective realisation of those plans, are essential
executive functions for independent, creative and socially constructive
behaviour (Lezak, 1982), for which Lezak forwarded the Tinkertoy Test.
Yet from Damasio’s point of view, in 2000 anyway, emotional valence is a
necessary adjunct to decision making. Indeed, limbic tagging, or
preservation of a prefrontal activity by stimulating pathways from limbic
system to prefrontal areas via the cingulate, is some evidence of this
correction mechanism (Gualtieri, 1995).
By 1982, when Lezak was querying the nature of assessing executive
functions, James Papez’s 1937 limbic formulations, and Paul MacLean’s
later and additional theories were yet to conclusively illuminate on the role
the amygdala in regulating human emotion (see Iverson, Kupfermann &
Kandel 2000; Killcross 2000). Evolution had found it critical to evaluate the
threat in another object’s facial expression, the approachability of another,
responses to linguistic threat, memory for emotional events, and necessary
learned responses to pleasant and aversive stimuli.
In concluding thus, it can be seen that self-regulation constitutes a second
order cybernetic process that allows the organism to consciously reflect on
its internal visceral self with some emotional valence, and place this position
in relation to an external context. By simulating this interaction across time
utilising verbal and visual working memory, the best temporally distant
outcomes can be determined and acted on accordingly. The above process is
a process in which the frontal lobes clearly play only a partial role, divisible
only perhaps according to some formulations of content (Lezak ,1995).
However, this is a process, and follows no normal distribution, being
unique to each individual, and involving multiple central nervous system,
emotional and somatic elements in a recursive, self-reflexive and
homeostatic way. In terms of this neuroepistemology, no testing instrument
has the necessary capacity to quantify the rapidly evolving content of this
process, as it is homeostatic in nature, and hence subject only to punctuation:
the nature of observation changes this process, and hence the test
room toolbox is empty of tools that have criterion validity, and is not a good
context to assess executive functioning (Barkley, 1998).
As Killcross (2000) notes, damage to the amygdala selectively impairs
the formation and utilisation of mental representations or rewarding
outcomes or goals. This again shows reference to the internal simulator of
outcomes, and the role of the amygdala, seldom if ever referred to in the
literature of executive outcomes. This is however part of what Blessing calls
the “real brain” (personal communication) in angry response to
considerations of isolated and artificial constructs such as ‘limbic structures’
or ‘temperolimbic’ areas in the Papez or MacLean formulations.
This would imply that trying to measure dysexecutive syndromes in the
presence of various pathologies would prove problematic, as behavioural
measures would lack ecological validity.
Dysexecutive syndrome and alcoholism: a case in point
An example which aptly demonstrates the difficulty of dynamic
assessment of executive functioning is that of alcoholic dementia in the
absence of dysmnesia, where multiple brain systems are involved: the
existence of such a syndrome is rendered contentious (Joyce, 1994;
Sugarman, 1992). Such a syndrome would be difficult to measure in terms
of its executive events. Even where ‘ecologically valid’ tools such as
Wilson et al.’s behavioural assessment of the dysexecutive syndrome BADS,
are used to address the controversial existence of an adaptive behaviour
syndrome, the experimenters note of the subjects who later were found to do
poorly on the BADS:
“……Nor did they show impaired social or occupational functioning or
present a significant deficit from a previous level of functioning” (Ihara,
Berrios & London, 2000, p. 732).
This is an interesting formulation: the existence of the dysfunction on the
testing is now seemingly held up as proof of actual brain dysfunction, either
that, or that a dysexecutive syndrome is something that only exists as a
response to a test which measures, well, the subject’s ability to do the test.
(Elsewhere, of course, Wilson and her colleagues have found ecological
validity for the BADS, in its tying together with patient and family report of
executive failures: Barbara Wilson, personal communication).
Ralph Tarter had found significant changes outside of the central nervous
system (cirrhosis, motor-nerve end-plate activity) that influenced subjects’
performance on various test instruments (Tarter, Panzak, Switala, Lu,
Simkevitz & Van Thiel 1997). Poor childhood executive functioning pre-
EVOLUTION AND EXECUTIVE FUNCTIONS
alcoholism was deemed a major factor (Ayataclar, Tarter, Kirisci & Lu
1999), and largely the tangle of environment and genotype was found to be
confounding in such an assessment (Vanyukov & Tarter, 2000). Recently,
there is substantive evidence that withdrawing from chronic alcohol
consumption may be the risky venture associated with alcohol abuse
(Davidson, Shanley & Wilce 1995; Hoffman 1995; Nutt 1999), not dose-
dependant on consumption, but in certain individuals (Nutt 1999). The
complex interaction of glutamate receptors and parvalbumin containing cells
(Krill, 1995) may influence the outcomes for executive functioning in this
way. The superior frontal association cortex, hypothalamus and cerebellum
are certainly involved, but conflicting evidence for damage to the
hippocampus, amygdala and locus ceruleus exists, and no change is found in
the basal ganglia, nucleus basalis or raphe nuclei (Harper, 1998).
With regard to memory, there is no surprise however in the findings that
confabulation is related to a sense of self and continuity (Mattioli, Miozzo &
Vignolo, 1999) or that this is related most strongly to temporal context
confusion (Schnider, von Daniken & Remonda, 2000).
It is clear that what defines executive dysfunction in the ecological sense
(‘anecdotal’ in Lezak’s formulation) is somewhat different to what testing
reveals on a neuropsychologically sensitive measure (as with Ihara’s group,
and which riles Eileen Joyce and Steven Bowden before her). The extent to
which interaction with a neuropsychological instrument corresponds to
interaction with the environment is after all a determination of its ecological
validity. In this context, what constitutes a “latent dysexecutive syndrome”
found on testing is unclear (Ihara et al. 2000 p 731). The answer perhaps lies
in their later comments:
“At the same time, analysis of individual cases confirms marked
interindividual and intraindividual differences in cognitive performances” (p
735) confirming what was said earlier, that such functioning is vitally unique
and not normally distributed.
A further discussion follows on the use of progressive matrices and the
nature of general ability but as Matarazzo (1990) has noted, the only real
common factor on which all testing loads is approximately that of
Spearman’s “g”, or a factor of general intelligence. Ihara et al. 2000 note
further that in “two thirds of these patients executive function impairment is
independent of general intelligence” (p 735) echoing Barkley’s (1998)
formulation that IQ is split off from executive functioning. None of this is
surprising as Ihara et al. 2000 later comment that the functional
independence of executive functioning from memory leaves room for further
investigation, but also: “we excluded patients with alcohol induced amnesic
disorders in the initial interview” (p 736) something Bowden stated should
not be done as it artificially biases the findings in alcoholism research.
It is thus clear from the above that patients with no clinically evident
difficulties in their lives may or may not respond to test instrument in ways
which may or may not reflect on brain pathology or normality in the face of
complex genotype-phenotype interactions, as Tarter noted, via multiple,
recursive pathways (Tarter et al., 1984), and against ‘substitute control
groups’ such as norm-based evaluation tables (Matarazzo, 1990).
The same difficulty faced Herrnstein & Murray (1994) in their evaluation
of the performances of various cultural groups. They ignored what an
individual may accomplish, and the variable, culturally loaded, cross-cultural
meaning of intelligent functioning (Nell, 2000).
Cross cultural evidence
Testing settings appear to be universals, but whether or not a subject
understands the demands of the test situation, in other words is test-wise or
not, will often depend on their knowledge of what a test situation in the
western paradigm really encompasses in terms of expectations.
The distant and silent tester, using supplied manuals with prescribed
language in non-western test paradigms, results in a form of gatekeeping,
favouring the advantaged and test-wise western subject, clearly in the service
of the tester, and not the subject (Taylor, 1999). What then is being
measured in executive terms is unclear.
Test situations and indeed, test manuals in western settings deliberately
minimise the interaction between tester and testee, and focus on correct
answers rather than processes, such as those important to learning (Taylor,
1994) although Walsh and other have constantly reiterated that the way a
subject fails is as important as their failure (Walsh, 1992). In this way,
western test procedures focus on overlearned information, not potential to
learn, thus working to the advantage of those who have actualised their
executive potential via interaction with education systems, and against those
who were not educated in terms of the demand of western paradigms.
Taylor (1994) identifies three approaches to cognitive assessment: firstly,
the structural approach, based on factor analytic research, secondly, the
information processing approach, and finally the dynamic approach, which
draws on the Vygotskyian-Lurian belief that the material conditions of
culture shape cognitive structures, in keeping with Barkley’s formulations
above. Luria’s field studies in Uzbekistan have been replicated in Africa
with near identical results (Nell, 2000).
EVOLUTION AND EXECUTIVE FUNCTIONS
Psychiatry too, as slow as neuropsychology in developing an awareness
of such principles, is now beginning to respond, wondering if it is measuring
the ‘right stuff’ in outcomes in schizophrenia (Green, Kern, Braff & Mintz
2000). It too is focusing on a more dynamic and integrated approach to
assessing the brain and behaviour (Koopowitz, 1999).
Despite these issues being common to most non-western settings, Global
IQ scores, common neuropsychology batteries, and various protocols of
assessment ignore what Taylor (1999) and others propose, namely the value
of a more dynamic testing approach, which would create programmes that
fulfill Vygotsky’s desire to foster the functions that have not yet matured,
but are still embryonic (Vygotsky, 1978). One sees discussion of this later
referred to as personal intelligence, or social competency, or fluid
intelligence in the Cattell (1971) mode (see also Ihara et al.’s 2000 mention
of this in passing).
Feuerstein (1979), Budoff (1987), Campione and Brown (1987), Carlson
and Wiedl (1979, 1992), Green et al. (op cit.) and others have attempted to
apply and develop Vygotsky’s original formulations of the zone of proximal
development (see Nell 2000), but with mixed, and much criticised success
(Taylor 1994; 1999).
Uncritical universalism thus dominates assessment of cognitive abilities
in western and non-western test settings, and some critics are now arguing
for a more humane relativism, with the expectation that wide variations in
normative performances must occur (Nell, 2000). Since test instruments can
be constructed that do not show statistical evidence of bias between
culturally divergent groups, (Taylor, 1999; TRAM 1 & 2, APIL-B), or
assume species wide comparisons (Lezak, 1995), a dynamic,
neurobehavioural assessment is feasible (Green et al., op cit.; Nell, 2000;
Sugarman, 2001). Such an approach would be of use where cultural effect is
noted and cannot be explained or dealt with (e.g. Johnson-Selfridge,
Zalewski & Aboudarham 1998) in the individual styles of executive
As Walsh noted in 1992, there is not a clear link between stimulus
material and the dimension or process being measured even in western
settings, and heavy demands are thus placed on the interpreter and tester
(Taylor, 1994; 1999) to extract diagnostically meaningful information, the
goal of clinical neuropsychological assessment (Matarazzo, 1990). Walsh
(1992) warns against such face validity pronouncements on performance
evaluations, and Franzen (1989) found that few tests in neuropsychology’s
tool kits share much in the domain of main effects variance anyway, really
only factoring down to a measure of overall ability (Matarazzo, 1990). The
inferential skill of the tester is still a factor, western setting or not, and in
non-western settings particularly, education is a factor, not race or ethnicity
(Perez-Arce, 1999; Ponton & Ardila, 1999). As in Australia, many societies
have significant immigrant populations, and in such groups, total number of
immigrants, occupational allegiance, education, and intended area of initial
residence impact on demographic variables known to have significant effects
on neuropsychological performance, especially in executive functioning
(Llorente, Ponton, Taussig & Satz 1999; Thomas, 1999).
While it must be accepted that the development of valid and reliable test
measures for executive functioning in non-western cultural groups must be
“based on empirical investigations” (Rey, Feldman, Rivas-Vaquez, Levin
and Benton, 1999, p. 593), a call echoed in Nell (2000), Taylor (1994) and
Lezak (1982), neuropsychological assessment in practice must not only fulfil
the criterion of being fair to non-western groups, but should also not
discriminate between western and non-western groups, whilst making
diagnostic interpretations mistakenly based on the culture, not the brain.
Culture-fair does not mean the translation of western tests into non-
western language (Artiola i Fortuny, Heaton & Hermosillo 1998; Ponton et
al 1996), since what is culturally acceptable in one instance, such as low
performance times indicate good executive achievement, may not be
acceptable in another, where speed is equated with sloppiness, and slowness
with being meticulous (Sugarman, 2001).
There is some value in creating novel tests that do not emanate, say from
US Army testing in the pre-WW I years (Lezak, 1995), nor label non-
western individuals with highly discrepant results that imply some inherent
cultural bias in the test battery, as in The Bell Curve (Herrnstein & Murray
1994). Developing special norm tables for individual groups on such
western tests may even be seen as discriminatory and legislated against (see
Section 106, American Civil Rights Act of 1991). The latter authors did after
all try to eliminate test entities that were overtly biased, but nevertheless
some groups in society must be left with the sense that on the attribute
supposedly measured, they are somewhat on the wrong side of the bell curve
In developed and developing societies such as Australia, this must lead to
the inevitable sidelining of growing, but impotent populations (see special
issue, Australian Psychologist, 2000, 35(2)), and as Herrnstein & Murray
(1994) illustrate. Such populations cannot always draw on overlearned
skills, as do the psychometrics of IQ tests, even when ‘norming’ these in the
Australian setting (Carstairs & Shores, 2000; Shores & Carstairs, 2000).
Culture-fair implies that the criterion-loading of the test, language
EVOLUTION AND EXECUTIVE FUNCTIONS
notwithstanding, be universal, and Nell (2000) and others argue
convincingly that the further you get from neurology, the worse that loading
becomes as a response to pseudo-evolutionary, discriminatory views of the
Although we live in gentler times than Luria….. (the) emphasis on
culture and the impact of culture on cognition is out of tune with the
universalism that psychology and neuropsychology have adopted as
a defence against the excesses of “culturalism” (Nell, 2000: p. 46).
Given the likelihood that executive functioning and culture have
interacted for millennia, the impact of one on the other reflexively makes the
goal of measuring executive functioning across cultures unlikely unless a
dynamic approach to testing is adopted.
As Homo Sapiens emerged from the sustained activity of evolutionary
pressure, a homeostatic neural mechanism evolved like any other, allowing
for one side of the mind to observe another, and in doing so, created a
simulation of the outside world and the organism itself in interaction. This
second order machinery freed the organism from total passivity under
evolution by allowing internal and accurate representations of the outside
world to exist, and for the organism to come to know how it feels about that
across time. The internal simulator could bind events across time, and in so
doing, came to understand its own mortality.
Truly homeostatic, such a mechanism acts upon the world, and in so
doing, acts upon itself, changing itself and allowing for the process of
ideational Darwinism and autopoiesis. Drawing on verbal and visual
working memory, and informed by emotion, the replications and simulations
of strings of behaviour may sometimes be imperfect, and hence are creative
or wrong, but always unique. Being unique they are not subject to statistical
reductionism, and hence the operations and output of such unique systems
are not normally distributed across populations, contexts or cultures. These
operations constitute the most subtle and central realm of human activity
When the tester interacts with the test taker, the testing situation alone
filters into the executive functions and insinuates its own process into the
simulations of the subject’s mind, and cannot stand aloof from it. A novel
view of dynamic assessment is needed in order to address these and other
Given the neuroepistemological concerns voiced here, and the
heterogeneity and paradoxical nature of executive functions, and the status
of investigation of the visceral brain, it is no small wonder our toolboxes are
empty as we confuse a process with the contents that have evolved over
millennia to produce the class of behaviours we call executive functions in
the test room, but are more grounded in the social interactions outside.
What we call executive functioning may be so intertwined with human
conscious awareness and emotion, as well as the rapidly fomenting and
changing homeostatic interaction with the prepotent environment, that
observing it changes its essential nature, and thus says more about the tool
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Recibido 25 Mayo, 2002
Aceptado 05 Junio, 2002